全文获取类型
收费全文 | 76篇 |
免费 | 0篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 2篇 |
环保管理 | 8篇 |
综合类 | 25篇 |
基础理论 | 18篇 |
污染及防治 | 11篇 |
评价与监测 | 9篇 |
社会与环境 | 2篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 5篇 |
2012年 | 8篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 4篇 |
2006年 | 1篇 |
2005年 | 6篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1989年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有76条查询结果,搜索用时 15 毫秒
51.
Edouard Kauffmann Horatiu Roman Georges Barau Hervé Dumas Annick Laffitte Alain Fourmaintraux Marc Bintner Hanitra Randrianaivo 《黑龙江环境通报》2003,23(2):163-165
The Jarcho–Levin syndrome is a specific form of spondylocostal/spondylothoracic dysostosis. There have been various classifications of this syndrome. We present the case of a severe prenatal Jarcho–Levin syndrome, diagnosed by ultrasound examination during the first trimester of pregnancy in a family with no previous medical history of an affected child. X-ray exploration, high-resolution spiral computed tomography and autopsy confirmed the diagnosis. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
52.
53.
Marguerite Hureaux Sarah Guterman Bérénice Hervé Marianne Till Sylvie Jaillard Sylvie Redon Myléne Valduga Charles Coutton Chantal Missirian Fabienne Prieur Brigitte Simon-Bouy Claire Beneteau Paul Kuentz Caroline Rooryck Nicolas Gruchy Nathalie Marle Morgane Plutino Lucie Tosca Celine Dupont Jacques Puechberty Caroline Schluth-Bolard Laurent Salomon Damien Sanlaville Valérie Malan François Vialard 《黑龙江环境通报》2019,39(6):464-470
54.
The emergence of the genetic code remains an enigma. Proposed mechanisms are based on random, historical, thermodynamic and natural selection. However, they introduce chance as a key factor for overcoming the difficulties encountered by the model. We propose here a model in which three successive levels of chemical specificity generated the nucleotide assignments of amino acids in the genetic code. The first level results from hydrophobic and stereospecific interactions between amino acids and short oligonucleotides (termed oligons). The second and third levels of specificity are determined by conditions of energy transfer from loaded oligons (amino acid-oligomer covalently linked) to formation of phosphodiester bond (second level of specificity) and peptidic bond (third level of specificity), while these reactions are catalyzed by RNA templates. This model is sustained by the relationships observed between dipole moments of the nucleotides (forming the anticodon) and reactivity of the amino acyl linkage of the loaded oligon. Moreover, analysis of modern tRNAs reveals that they were probably generated by loose duplication of the nucleotide sequence forming the oligons, after emergence of the 'genetic code.' Indeed, the similarity of nucleotide composition with that of the anticodon decreases with the tRNA domain's distance from the anticodon, but the acceptor stem is relatively more similar to the anticodon than other stems closer to it. This would be because energy transfer constraints that existed between anticodon and amino acid in prebiotic loaded oligonucleotides still affect the structures of modern tRNA acceptor stems. In the model presented, the genetic code is inherent to the most archaic 'molecular physiology' in protolife, even before emergence of a functional 'protein world.' Simple physical processes, in which a level of specificity is integrated in an emerging meta-structure expressing new properties, generate a parsimonious and realistic explanation of emergence of the genetic code. 相似文献
55.
Public Perception as a Barrier to Introducing Wood in Rivers for Restoration Purposes 总被引:2,自引:0,他引:2
Piégay H Gregory KJ Bondarev V Chin A Dahlstrom N Elosegi A Gregory SV Joshi V Mutz M Rinaldi M Wyzga B Zawiejska J 《Environmental management》2005,36(5):665-674
Reintroduction of wood in rivers for restoration purposes is now recognized in a positive way by scientists. Nevertheless,
the perception of wood in riverscapes is strongly affected by the socio-cultural environment. This cultural influence might
explain why wood reintroduction is accepted and promoted in some regions of the world but not in others, despite the demonstrated
ecological benefits. From an extensive student perception survey, we show that most of the groups from nine countries in the
world considered riverscapes with wood to be less aesthetic, more dangerous, and needing more improvement than riverscapes
without wood. By contrast, this way of thinking was not observed in Germany, Sweden, and Oregon (USA), where the first instances
of wood reintroduction occurred. 相似文献
56.
Variations in the birth sex ratio and neonatal mortality in a natural herd of horses 总被引:3,自引:0,他引:3
Anne-Marie Monard Patrick Duncan Hervé Fritz Claudia Feh 《Behavioral ecology and sociobiology》1997,41(4):243-249
Variations in birth sex ratios and sex differences in juvenile mortality occur in a number of mammalian species, and in many
cases have been linked to resource availability. Most of these biases in offspring sex ratios concern polygynous species with
pronounced sexual dimorphism, and where females only are philopatric. Data on species with unusual life-history strategies,
such as slight sexual dimorphism or dispersal by both sexes, are of particular interest. In this study of a natural herd of
horses (Equus caballus) which experienced an eruptive cycle, and therefore a period of nutritional stress, male offspring had higher neonatal mortality
rates in nutritionally poor years than in good ones, whereas “year quality” had no effect on the mortality of female offspring;
year quality could therefore be used by mares as predictor of sex-specific offspring survival. We show that the environmental
conditions that predicted lower survival of males were negatively related to their production: the birth sex ratio the following
year was female-biased; and mares were less likely to produce a son when they had produced a son the preceding year. There
was no significant effect of mother's parity, age or rank, or the timing of conception or birth on offspring sex ratios. The
mechanism leading to biases in the birth sex ratio could have been the loss of male embryos by mares that did not foal. As
there was no evidence for selective abortion of male foetuses in females that did foal the next year, it is not necessary
to invoke maternal adjustment, though this remains a possibility. Finally, there was a suggestion that male offspring were
more costly to raise than females, since mothers that reared a son in poor years tended to experience an increase in the interbirth
interval between their two subsequent offspring.
Received: 28 December 1996 / Accepted after revision: 27 July 1997 相似文献
57.
Tanja Schwander Hervé Rosset Michel Chapuisat 《Behavioral ecology and sociobiology》2005,59(2):215-221
Division of labour among workers is central to the organisation and ecological success of insect societies. If there is a genetic component to worker size, morphology or task preference, an increase in colony genetic diversity arising from the presence of multiple breeders per colony might improve division of labour. We studied the genetic basis of worker size and task preference in Formica selysi, an ant species that shows natural variation in the number of mates per queen and the number of queens per colony. Worker size had a heritable component in colonies headed by a doubly mated queen (h
2=0.26) and differed significantly among matrilines in multiple-queen colonies. However, higher levels of genetic diversity did not result in more polymorphic workers across single- or multiple-queen colonies. In addition, workers from multiple-queen colonies were consistently smaller and less polymorphic than workers from single-queen colonies. The relationship between task, body size and genetic lineage appeared to be complex. Foragers were significantly larger than brood-tenders, which may provide energetic or ergonomic advantages to the colony. Task specialisation was also often associated with genetic lineage. However, genetic lineage and body size were often correlated with task independently of each other, suggesting that the allocation of workers to tasks is modulated by multiple factors. Overall, these results indicate that an increase in colony genetic diversity does not increase worker size polymorphism but might improve colony homeostasis. 相似文献
58.
Pierrick Blanchard Rodolphe Sabatier Hervé Fritz 《Behavioral ecology and sociobiology》2008,62(12):1863-1868
Theory predicts that individuals at the periphery of a group should be at higher risk than their more central conspecifics
since they would be the first to be encountered by an approaching terrestrial predator. As a result, it is expected that peripheral
individuals display higher vigilance levels. However, the role of conspecifics in this “edge effect” may have been previously
overlooked, and taking into account the possible role of within-group competition is needed. Vigilance behavior in relation
to within-group spatial position was studied in impalas (Aepyceros melampus) feeding on standardized patches. We also controlled for food distribution in order to accurately define a “central” as opposed
to a “peripheral” position. Our data clearly supported an edge effect, with peripheral individuals spending more time vigilant
than their central conspecifics. Data on social interactions suggest that it was easier for a foraging individual to defend
its feeding patch with its head lowered, and that more interactions occurred at the center of the group. Together, these results
indicate that central foragers may reduce their vigilance rates in response to increased competition. Disentangling how the
effects of competition and predation risk contribute to the edge effect requires further investigations. 相似文献
59.
A statistical study was performed over 145 profiles of meteorological balloons, equipped with microthermal sensors, from the
ground to the midstratosphere. This study put into evidence the lognormal distribution of the fluctuations of the structure
constant of temperature, the fluctuations of the buoyancy force and the vertical shear of the horizontal wind speed. We show
that these quantities, computed over a large scale (100 m), are correlated up to the midstratosphere. A model is adjusted
to estimate the optical turbulence strength from the macroscopic meteorological parameters. The model performances, to estimate and forecast the strength and the altitude
of the optical turbulent layers, are quantified and compared with other already defined models. This model was shown to have
the best performances and put into evidence a new relation to describe the turbulence on a large scale. 相似文献
60.
We derive conditions that must be satisfied by the primitives of the problem in order for an equilibrium in linear Markov
strategies to exist in some common property natural resource differential games. These conditions impose restrictions on the
admissible form of the natural growth function, given a benefit function, or on the admissible form of the benefit function,
given a natural growth function.
相似文献
Gérard GaudetEmail: |